Question

The steps to check if $x=3$ is the solution of the equation $4x=12$ are given below. Identify the first error, if any.

• A. Step 2: Substitute the value of the given variable, $x=3$ in the expression, $4x$, and evaluate LHS.
• B. Step 4: So, LHS $\ne$ RHS implies $x=3$ makes the equation, $4x=12$, false
• C. Step 3: LHS $=4\times 3=12$ and RHS $=12$
• D. Step 1: Separate the equation. There is a $4x$ in the LHS and $12$ in the RHS

Answer 1

The correct option is B Step 4: So, LHS $\ne$ RHS implies $x=3$ makes the equation, $4x=12$, false

Step 1: In the equation, $4x$ is the LHS, and $12$ is the RHS.
Step 2: Substitute the value of the given variable, $x=3$ in the expression, $4x$, and evaluate LHS.
Step 3: LHS $=4\times 3=12$ and RHS $=12$
Step 4: So, LHS $=$ RHS implies $x=3$ makes the equation $4x=12$ true.
So, the first error happens at step $4$.
Option D is correct.